1. Field of the Invention
The instant invention relates to signaling apparatus. More particularly, the invention relates to such apparatus which is useful in a motor vehicle equipped with both an ignition switch and a locking device, and which is operatively associated with the locking device, especially to warn that a key has been left in the locking device when a door of the vehicle has been opened.
2. Description of the Prior Art
Signaling devices for use in motor vehicles, including ones which provide an audible or visual warning when a door of the vehicle is opened while a key remains in the ignition switch thereof, are well known. Also known are signaling devices which can be operatively associated with steering lock antitheft apparatus for vehicles. Such antitheft apparatus usually includes an ignition switch which must be closed to enable starting of the vehicle engine. Frequently, rotation of a key in such apparatus first disengages a latch from the steering shaft of the vehicle and then closes the ignition switch. Many conventional steering lock/ignition switch devices can be rotated to at least four different angular positions, for example corresponding to STOP, GARAGE, RUN and START. For instance, in the STOP position the ignition key can be inserted and extracted, but the steering shaft remains locked. In the GARAGE position the ignition key can also be inserted and extracted, but the steering shaft remains unlocked. In the RUN and START positions the ignition key can be neither inserted nor extracted and the steering shaft remains unlocked.
U.S. Pat. No. 2,786,194 discloses a signaling device for use with an ignition switch of a motor vehicle. The device is said to provide both a visual and an audible signal whenever the ignition switch is in an "off" position with the key inserted, thereby to provide a reminder that the key is inserted and the switch is in that position.
U.S. Pat. No. 3,569,930 discloses a key-operated antitheft lock for a vehicle steering shaft, and an alarm operable, unless the steering shaft is locked, whenever a door of the vehicle is opened.
U.S. Pat. No. 3,629,818 discloses another antitheft device for a motor vehicle; the device comprises a steering shaft lock and two switches operated by movement of the lock. One of the switches is closed when a door of the vehicle is open and the other is closed when the steering shaft is not locked. An alarm operatively connected through the switches is energized if the door is opened when the steering shaft is unlocked. The device also uses a relay switch having a solenoid coil to control energization of the alarm; in addition, at least three mechanical switches are required for operation of the device.